Funding is requested to continue training individuals for careers in cancer research. Predoctoral trainees are Ph.D. or M.D./Ph.D. candidates who conduct cancer-related thesis research at The Wistar Institute in partial fulfillment of the Ph.D. requirements of the University of Pennsylvania. Postdoctoral training is designed to prepare individuals for independent research careers in cancer-related areas in basic research and clinical settings. This program is devoted to laboratory research training. In addition, this program offers two lecture courses in the Molecular and Clinical Aspects of Cancer Biology. Trainees are also provided annually with training on The Responsible Conduct of Research, in alternate years attending a Research Ethics Lecture series and participating in Research Ethics Training Discussion Groups. Trainees present their research accomplishments to the Institute annually and are active participants in Institute Lecture series and informal research conferences. The proposed trainers head 21 independent laboratories. The research of the participating faculty includes both basic research as well as "translational" and clinical research projects in three of the major current focuses in cancer research: mechanisms of regulation of gene expression and how they are perturbed in human cancers; the cellular and molecular basis of tumor development and progression; and in basic immunology and in the burgeoning area of immunotherapy of cancer. Overall, the program is characterized by training opportunities in highly interactive research programs conducted by the participating faculty that have resulted in many collaborative publications. All participating faculty continually succeed in attracting excellent predoctoral and postdoctoral fellows to participate in the research programs described. Each of the participating faculty have successfully competed for federal and non-federal grant support. Over 70 percent of the participating faculty is supported by the NCI or other national cancer research funding agencies including the American Cancer Society and DOE or Army grants dedicated to the support of cancer research. Altogether, this program offers training in "cutting edge" basic cancer research that will prepare the trainee for a productive career in science and advance our understanding of the malignant process.